In a network analyzer, a transfer switch connects the test signal source to one port of the device under test and terminates the remaining ports in a low-reflection load. The ideal transfer switch has a low, repeatable loss in the test signal path. In some cases, it is also advantageous to have gain in the signal path, provided the gain is stable and repeatable.
In addition, the transfer switch must provide a high degree of isolation in all of the terminated paths. Any signal leakage directly from the through path to the terminated paths bypasses the device under test and causes cross-talk. Further, for measurement accuracy, it is advantageous to have terminations that have identical impedance for each of the terminated paths. Finally, each port should have the same impedance whether that port is acting as a load or a source.
Broadly, it is the object of the present invention to provide an improved transfer switch.
These and other objects of the present invention will become apparent to those skilled in the art from the following detailed description of the invention and the accompanying drawings.